Defect identification method for transient recording type fault indicator

Abstract

The application provides a defect identification method for a transient recording wave type fault indicator, and belongs to the field of power equipment. The method comprises the following steps: obtaining a main station fault recording wave file; judging whether there is a device offline condition through the number of the fault recording wave file; judging whether there is a collection unit offline condition through the completeness of the fault recording wave file data; obtaining an i-th extreme value time point t1, an i+1-th extreme value time point t4 of the A phase, and an extreme value time point t2 of the B phase and an extreme value time point t3 of the C phase between t1-t4 in the fault recording wave file; judging whether the fault indicator exists a reverse installation or a wrong phase installation condition according to t1, t2 and t3; obtaining fault waveforms of the ABC three-phase voltage at a fault moment in all the fault recording wave files; and determining whether the fault indicator exists a wrong phase installation condition through the comparison of the same phase fault waveforms between different fault recording wave files. The application can identify the offline, reverse or wrong phase defects of the transient recording wave type fault indicator.

Description

Technical Field

[0001] This invention belongs to the field of power equipment technology, and specifically relates to a defect identification method for transient waveform fault indicators. Background Technology

[0002] Single-phase grounding faults are frequent in power distribution lines. Transient waveform recording fault indicators have been widely adopted because they can quickly locate faulty sections, shorten fault handling time, and improve operation and maintenance efficiency. All transient waveform recording fault indicators installed on the same busbar can trigger three-phase synchronous waveform recording of current and electric field when a grounding fault occurs, and all of them report the fault waveform files to the distribution automation master station. The master station combines the fault waveform files with the line topology to complete the fault location and distribute the information to the operation and maintenance team.

[0003] However, reviewing the reported fault waveforms revealed several issues: insufficient completeness of the recorded waveforms at the time of the fault, excessive zero-sequence current under normal conditions, and inconsistencies in the three-phase voltage waveform characteristics across different recorded waveforms. These issues exposed defects in the transient waveform-based fault indicator, including offline operation, non-compliant installation, and communication abnormalities. Under these circumstances, the accuracy and reliability of fault segment assessment are significantly reduced. Therefore, identifying and analyzing the defects of transient waveform-based fault indicators to ensure the reliability of the entire fault location process is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a defect identification method for transient waveform fault indicators, which addresses the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A defect identification method for a transient waveform fault indicator includes: Obtain the main station fault recording file; The number of fault recording files determines whether the device is offline; Determine whether the acquisition unit is offline by checking the integrity of the fault recording data. Obtain the i-th extreme moment t1 and the (i+1)-th extreme moment t4 of phase A in the fault recording file, as well as the extreme moment t2 of phase B and the extreme moment t3 of phase C, which are located between t1 and t4. Determine whether the fault indicator is installed in reverse or out of phase based on t1, t2, and t3; Obtain the fault waveforms of the three-phase voltages (A, B, and C) at the time of the fault from all fault recording files; The presence of mis-phase installation of the fault indicator is determined by comparing the in-phase fault waveforms between different fault recording files.

[0006] Furthermore, all extreme value moments are either peak moments or valley moments.

[0007] Furthermore, the method for determining whether the fault indicator is installed in reverse based on t1, t2, and t3 includes: t1, t2, and t3 are not an arithmetic sequence with a tolerance of d, and t1, t2, and t3 cannot form an arithmetic sequence with a tolerance of d, where d is one-third of the period.

[0008] Furthermore, the method for determining whether the fault indicator is installed out of phase based on t1, t2, and t3 includes: t1, t2, and t3 are not an arithmetic sequence with a tolerance of d, and t1, t2, and t3 can form an arithmetic sequence with a tolerance of d, where d is one-third of the period.

[0009] Furthermore, the fault waveform is the voltage waveform of the three phases ABC 1-3 cycles after the fault time.

[0010] Furthermore, the presence of mis-phase installation of the fault indicator is determined by comparing the in-phase fault waveforms between different fault recording files: the fault waveforms of all fault recording files are compared between in-phase files. If there are inconsistencies between in-phase files, the consistent fault waveforms are classified, and the type of fault waveform that is not the most numerous is identified as the abnormal waveform. The acquisition unit of the fault indicator corresponding to the abnormal waveform is then determined to be mis-phase installed.

[0011] Furthermore, in the i-th extreme time point, i∈{1,2,3}.

[0012] Furthermore, the method for determining whether an acquisition unit is offline based on the integrity of the fault recording data includes: if the measured values ​​of current and voltage in a certain phase are both zero for 12 cycles, it indicates that the corresponding acquisition unit is offline.

[0013] Furthermore, the system also uses the disconnection remote signaling item of the fault indicator to determine whether there is a communication anomaly.

[0014] Furthermore, the system also uses the disconnection remote signaling item of the fault indicator acquisition unit to determine whether there is a communication anomaly.

[0015] Currently, my country's 10kV distribution network generally adopts an operation mode where the neutral point is either ungrounded or grounded through an arc suppression coil, i.e., a low-current grounding mode. In low-current grounding systems, 80% of system faults are single-phase grounding faults. When a single-phase grounding short-circuit fault occurs in a low-current grounding system, the fault current is relatively small, and protection criteria are not required to immediately activate and disconnect the fault. Therefore, the distribution system can continue to operate energized for 1 to 2 hours. However, the voltage to ground of the non-faulty phase lines will rise to the line voltage, posing a significant threat and burden to the insulation of lines and equipment, and may even develop into a multi-point grounding fault. Furthermore, with increasing user demands for power quality and reliability, and to ensure the safety of personnel and electrical equipment near the fault point, the distribution system is required to have the capability for rapid fault identification, location, and timely power restoration, enabling power workers to promptly detect and clear grounding fault points.

[0016] my country's power distribution network is characterized by multiple voltage levels, complex network structure, and poor safety environment. In particular, in some mountainous and rural areas, the power distribution lines are long, the operating environment is poor, and the maintenance cost is high. The method of relying solely on power workers to manually inspect the lines to isolate fault points is not only labor-intensive, time-consuming, and costly, but also cannot meet the requirements of the power distribution system to quickly restore power supply after a fault. Therefore, some fault indication devices have begun to be used on power distribution lines. Among them, the transient waveform fault indicator is a new type of fault indicator that has emerged with the development of communication technology.

[0017] During power grid operation, the need for rapid and accurate fault location and diagnosis necessitates the accurate and real-time acquisition of electrical quantities such as line voltage, line current, line load, and transmitted power. This allows power workers to promptly understand the operating status of the power system and respond appropriately to faults. The transient waveform recording fault indicator is an improvement upon traditional single-function fault indicators, featuring real-time waveform recording capabilities. It records power system parameters and electrical quantity waveforms before, during, and after a fault, transmitting them to the master station in real time. This enables workers to quickly identify, correctly locate, and promptly repair faults.

[0018] Transient waveform fault indicators typically consist of three acquisition units, each matched one-to-one with one of the three phases (A, B, and C), and one aggregation unit. All acquisition units are communicatively connected to the aggregation unit. When the fault indicator detects a line fault, the aggregation unit transmits the fault time data collected by the acquisition units to the backend of the distribution automation master station. The installation of the acquisition units requires matching the corresponding phase lines and adhering to a unified power flow direction; the direction of the current flowing through the acquisition unit must be positively correlated with the direction of the electric field strength. However, currently, some busbars do not have three-phase markers, leading to frequent instances of acquisition units being installed incorrectly or in reverse. When an acquisition unit is installed in reverse, the synthesized zero-sequence current value is too large, affecting the accuracy of ground fault diagnosis. When an acquisition unit is installed incorrectly, the phase line where the ground fault occurred cannot be accurately located.

[0019] In addition, wireless communication is often used between the acquisition unit and the aggregation unit of the transient waveform fault indicator, and between the aggregation unit and the distribution automation master station. However, in the complex electromagnetic environment near high voltage, wireless communication may become unstable, causing the transient waveform fault indicator to go offline or a certain acquisition unit to go offline, affecting the normal operation of the transient waveform fault indicator.

[0020] Therefore, in order to make the transient waveform fault indicator function fully and improve the accuracy of single-phase grounding fault assessment in the distribution network, it is necessary to identify defects such as offline, reverse, and phase error in the transient waveform fault indicator.

[0021] The offline status of equipment or acquisition units can be determined by the quantity and completeness of fault waveform files, while the reverse and phase misalignment of acquisition units can be determined by the waveforms in the fault waveform files. In cases of reverse or partial phase misalignment of the acquisition unit, the fault waveform files recorded by the transient waveform fault indicator differ significantly from the normal three-phase AC waveform. Therefore, defects such as reverse installation can be identified by comparing them with the normal waveform. While there are many existing methods for waveform comparison, the algorithms for waveform comparison are complex and computationally intensive. Therefore, for easily identifiable defects such as reverse installation and partial phase misalignment, this application employs a method of extracting key features from the waveform for comparison. Specifically, in a normal three-phase electrical waveform, the time difference between the continuous peaks or valleys of the A, B, and C phase current or voltage waveforms is one-third of the period. Based on this, this application first determines whether the three consecutive extreme time points of the A, B, and C phases in the waveform file form an arithmetic sequence with a tolerance of one-third of the period.

[0022] However, when the above judgment is negative, although it certainly indicates that the three-phase data of phases A, B, and C in the fault recording file are abnormal, it is still necessary to distinguish whether the abnormality of the three-phase data is due to reverse or phase error; when the above judgment is positive, it does not prove that the data of phases A, B, and C in the fault recording file are normal, and phase error may still exist.

[0023] Therefore, this application, based on determining whether the three extreme time points form an arithmetic sequence with a tolerance of one-third of the period, further determines whether the three extreme time points can form an arithmetic sequence with a tolerance of one-third of the period. If they can form such a sequence, it indicates that the data for phases A, B, and C are still normal data, and the problem is merely due to a disordered sequence, i.e., the acquisition unit is installed in the wrong phase. If they cannot form such a sequence, it indicates that one phase of the data for phases A, B, and C is abnormal reversed data, confirming that the acquisition unit has been installed in reverse.

[0024] In the fault recording files with partial phase misalignment, the three extreme time points are still an arithmetic sequence with a tolerance of one-third of the period. Therefore, for the case where the three extreme time points are an arithmetic sequence with a tolerance of one-third of the period, it is still necessary to continue to verify the waveform to rule out possible phase misalignment.

[0025] When a single-phase ground fault occurs on the busbar, the voltage fault waveforms of all fault indicators on the same phase are consistent, while the voltage fault waveforms of different phases are inconsistent. Based on this, this application finally obtains the fault waveforms of the three-phase voltages (A, B, and C) from all recorded waveforms, determines the fault waveform of one correctly installed fault indicator as the reference waveform, and judges whether the fault waveforms in other recorded waveforms are consistent with the reference waveform to determine whether the corresponding fault indicator has been installed in the wrong phase.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: This application can identify defects that may exist in transient waveform fault indicators, such as equipment offline (fault indicator offline), acquisition unit offline, communication abnormality (communication abnormality between collection unit and master station, communication abnormality between acquisition unit and collection unit), equipment reverse (acquisition unit is installed in reverse), and equipment phase error (acquisition unit is installed in the wrong phase), providing a basis for improving the single-phase grounding fault handling capability of distribution networks.

[0027] This application identifies defects in transient waveform recording fault indicators step by step by verifying the quantity of fault recording files, the integrity of the recording files, the key waveform features in the recording files, and the consistency of fault waveforms in the recording files. The entire verification process progresses from simple to complex, and during execution, it can gradually identify fault indicators with defects, ultimately reducing the number of recording files to be verified in subsequent complex verification processes, thereby improving execution efficiency.

[0028] This application addresses the issues of reverse installation and partial phase misalignment installation of the acquisition unit. It extracts the extreme point moments of the three phases in the waveform as key verification features. Finally, it uses whether these extreme point moments form an arithmetic sequence with a tolerance of one-third of the period, and whether such a sequence can be constructed, to determine the reverse installation and partial phase misalignment defects of the acquisition unit. Furthermore, for the waveform files that pass the above verification, a fault waveform comparison method is still used to verify whether other phase misalignment defects exist. Attached Figure Description

[0029] The present invention will now be described in further detail with reference to the accompanying drawings.

[0030] Figure 1 Schematic diagram of a transient waveform fault indicator; Figure 2 One of the flowcharts of this invention; Figure 3 : The second flowchart of this invention; Figure 4 One of the schematic diagrams of the fault recording file of the present invention (offline defect of the acquisition unit); Figure 5 : The second schematic diagram of the fault recording file of the present invention (reverse defect of the acquisition unit); Figure 6 : The third schematic diagram of the fault recording file of the present invention (phase misalignment defect of the acquisition unit); Figure 7 : The fourth schematic diagram of the fault recording file of the present invention (normal waveform); Figure 8 : Fifth schematic diagram of the fault recording file of the present invention (phase misalignment defect of the acquisition unit). Detailed Implementation

[0031] To better understand the present invention, the content of the invention is further clearly illustrated below with reference to embodiments and accompanying drawings. However, the scope of protection of the present invention is not limited to the embodiments described below. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0032] In this application document, the terms "fault indicator" or "device" are used in certain statements and figures to refer to the transient waveform fault indicator.

[0033] like Figure 1The diagram shows the structure of a transient waveform fault indicator, including a data acquisition unit and a data aggregation unit. Three data acquisition units are installed one-to-one on matched phase lines, and the data aggregation unit is communicatively connected to the three data acquisition units. When the fault indicator detects a line fault, the data aggregation unit transmits the data collected by the data acquisition units before and after the fault to the backend of the distribution automation master station. In practical engineering applications, the fault indicator must ensure the accurate installation of the data acquisition units, which must be installed phase-by-phase according to the unified power flow direction. However, fault indicator equipment failure, unstable communication, and other reasons can lead to various offline defects, especially when the busbar lacks three-phase identifiers, where data acquisition units often experience phase misalignment or reverse installation problems. Therefore, common defects in fault indicators include: equipment offline (fault indicator offline), data acquisition unit offline, communication anomalies (abnormal communication between the data aggregation unit and the master station, abnormal communication between the data acquisition unit and the data aggregation unit), reversed equipment (data acquisition unit installed in reverse), and phase misalignment (data acquisition unit installed in the wrong phase). This application aims to identify these defects.

[0034] See Figures 2-8 The purpose of this embodiment is to provide a defect identification method for a transient waveform fault indicator. The identification method includes: Step S1: Obtain the fault recording file.

[0035] When a single-phase ground fault occurs on a busbar, the fault indicator installed on the busbar can synchronously record the three-phase current and voltage waveforms before and after the fault, and automatically transmit the waveform files to the distribution automation master station. The fault indicator's waveform files contain data for the four cycles before the fault and the eight cycles after the fault. The zero-sequence current used for fault detection is synthesized from the currents of phases A, B, and C. When the fault indicator is defective, it will affect the accuracy of the zero-sequence current.

[0036] This step automatically retrieves fault waveform files reported by all fault indicators installed on the same bus from the distribution automation master station.

[0037] Step S2: Determine whether there is a device offline status by the number of fault recording files.

[0038] The number of fault recording files obtained is denoted by m; the total number of fault indicators installed on this bus is denoted by n.

[0039] If m<n, it indicates that some fault indicators have not transmitted the fault recording files. By comparing the fault recording files with the installed fault indicators, the defective fault indicators that fail to report the fault recording files are identified. Then, the master station background is queried to check whether there is an offline remote signaling item for the defective fault indicator within two hours. If the offline remote signaling item exists, the defect state of the fault indicator is determined as device offline; if the offline remote signaling item does not exist, it indicates that there is communication abnormality or unstable communication between these defective fault indicators and the master station, and the defect state of the fault indicator is determined as communication abnormality.

[0040] The offline remote signaling item is a remote signaling parameter for monitoring whether the device loses connection or communication is interrupted, and is used to indicate that the device or signal source is in an offline or communication fault state.

[0041] If m=n, the subsequent steps are continued.

[0042] In step S3, it is determined whether the acquisition unit is offline according to the integrity of the fault recording file data.

[0043] A single fault recording file is extracted sequentially, and the measured values of current and voltage of the ABC three phases within 12 cycles in the fault recording file are read. If all the measured values of a certain phase are zero, it indicates that the acquisition unit installed on that phase is abnormal. Then, the master station background is queried to check whether there is an offline remote signaling item for the abnormal acquisition unit within two hours. If the offline remote signaling item exists, the defect state of the corresponding fault indicator is determined as acquisition unit offline; if the offline remote signaling item does not exist, it indicates that there is communication abnormality or unstable communication between these acquisition units and the aggregation unit, and the defect state of the corresponding fault indicator is determined as communication abnormality.

[0044] As Figure 4 shown in the fault recording file, the voltage and current data of phase C are all zero, which indicates that the acquisition unit installed on phase C of the corresponding fault indicator is abnormal.

[0045] For fault indicators with communication abnormality, their remote measurement values within two hours shall be checked to troubleshoot the cause of the communication abnormality.

[0046] If the current and voltage data of the ABC three phases within 12 cycles in the read fault recording file are not all zero, the subsequent steps are continued.

[0047] In step S4, the i-th extreme time point t1 and the (i+1)-th extreme time point t4 of phase A in the fault recording file are obtained, as well as the extreme time point t2 of phase B and the extreme time point t3 of phase C located between t1 and t4; i∈{1,2,3}.

[0048] An extreme value point refers to the moment when the measured quantity (current or voltage) is at its peak (maximum) or valley (minimum). This moment can be the difference between the measured quantity and the reference moment (such as the fault moment in the fault waveform file), measured in milliseconds (ms). In this step, the extreme value points are selected as either peak moments or valley moments. To eliminate the influence of the fault on the measured quantity, the extreme value point before the fault should be selected. Since the fault waveform file contains four cycles before the fault, i∈{1,2,3}.

[0049] Step S5: Determine whether the fault indicator is installed in reverse or in the wrong phase based on t1, t2 and t3.

[0050] Since the normal phase sequence difference of the three phases A, B, and C is 120°, the time difference d between adjacent extreme points of the three phases A, B, and C is T*120 / 360=T / 3, where T is the AC current cycle in the bus (also the time difference between t1 and t4), and d is one-third of the cycle. At a power frequency of 50Hz, the AC current cycle T is 20ms, and d is 6.67ms. Therefore, assuming the fault indicator and its acquisition unit are functioning normally, t1-t2 should be d, and t2-t3 should also be d, meaning t1, t2, t3, and t4 form an arithmetic sequence with a tolerance of d.

[0051] Therefore, when t1, t2, t3 are not an arithmetic sequence with tolerance d, it indicates that the three-phase data of ABC in the fault recording file are abnormal. Subsequently, t1, t2, t3 are sorted in ascending order to determine if the sorting result is an arithmetic sequence with tolerance d. That is, it is determined whether t1, t2, t3 can form an arithmetic sequence with tolerance d. If not, it is determined that a certain acquisition unit in the fault indicator is reversed (incorrect installation direction); if so, it is determined that the acquisition unit of the fault indicator is in the wrong phase, i.e., installed on the wrong phase line.

[0052] like Figure 5 In the fault recording file shown, the power frequency is 50Hz. The time difference between adjacent extreme values ​​of the measured quantities in phases A and B is less than one-third of the period T. Therefore, the adjacent extreme values ​​of phases A, B, and C cannot form an arithmetic sequence with a tolerance of 6.67ms, indicating that a certain acquisition unit in the fault indicator is reversed.

[0053] like Figure 6 In the fault recording file shown, the power frequency is 50Hz, and the selected extreme time points t1, t2, t3 are not an arithmetic sequence with a tolerance of 6.67ms. However, t1, t3, t2 after ascending sorting are an arithmetic sequence with a tolerance of 6.67ms, indicating that the acquisition unit inside the fault indicator is installed in the wrong phase.

[0054] However, in cases where the acquisition units are installed in a misaligned manner, such as when the corresponding acquisition units for phases ABC are sequentially installed on phases BCA, the t1, t2, and t3 obtained in step S4 are still an arithmetic sequence with a tolerance of d. Therefore, step S5 cannot eliminate this misalignment situation. Subsequent steps are used to identify similar misalignment installation situations.

[0055] If t1, t2, t3 are an arithmetic sequence with common difference d in the above process, then continue with the subsequent steps.

[0056] Step S6: Obtain the fault waveforms of the three-phase voltages (A, B, and C) at the time of the fault in all fault recording files.

[0057] When a single-phase ground fault occurs on the busbar, the instantaneous voltage waveform after the fault occurs is the fault waveform, which is the voltage waveform of the three phases ABC after the fault occurs in 1-3 cycles.

[0058] Step S7: Determine whether the fault indicator is installed in the wrong phase by comparing the in-phase fault waveforms between different fault recording files.

[0059] When a single-phase ground fault occurs on the busbar, the voltage fault waveforms of all fault indicators on the same phase are consistent, while the voltage fault waveforms of different phases are inconsistent. Based on this, this step obtains the fault waveforms of the three-phase voltages (A, B, and C) in all recorded waveform files. By comparing the fault waveforms between different fault recorded waveform files, it is determined whether these fault indicators are installed in the wrong phase.

[0060] Specifically, the fault waveforms of phase A, phase B, and phase C voltages are sequentially acquired from all fault recording files. The fault waveforms between the same phases are compared. If the changes in the fault waveforms between the same phases are consistent, it is determined that no defect has been found in the fault indicator. If there are inconsistencies between the same phases, the fault waveforms with consistent waveforms between the same phases are categorized. The most frequent type of fault waveform is identified as the normal waveform, and the other fault waveforms are identified as abnormal waveforms. It is then determined that the acquisition unit of the fault indicator corresponding to the abnormal waveform is installed in the wrong phase.

[0061] Waveform comparison can be performed using algorithms such as cross-correlation and phase correlation, or by visual comparison; no restrictions are imposed here.

[0062] like Figure 7 , Figure 8 In the fault recording file shown, the fault time is at 0ms. Figure 7 and Figure 8 The fault waveforms are inconsistent; if determined statistically... Figure 7 If the fault waveform is a normal waveform, then it can be determined that... Figure 8 The fault waveform is an abnormal waveform, indicating that... Figure 8 The acquisition unit in the corresponding fault indicator is installed in the wrong phase.

[0063] Of course, the number of fault indicators installed in some busbars is small. When the waveforms of the same phase fault are inconsistent between different waveform recording files, it may not be possible to determine the normal or abnormal waveform using statistical methods. In this case, the staff can manually determine the fault waveform by observing the fault waveform, or the maintenance personnel can determine it on-site.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A defect identification method for a transient waveform fault indicator, characterized in that: include: Obtain the main station fault recording file; The number of fault recording files determines whether the device is offline; Determine whether the acquisition unit is offline by checking the integrity of the fault recording data. Obtain the i-th extreme moment point t1 and the (i+1)-th extreme moment point t4 of phase A in the fault recording file, as well as the extreme moment point t2 of phase B and the extreme moment point t3 of phase C, which are located between t1 and t4; all of the above extreme moment points are extreme moment points before the fault. Determine whether the fault indicator is installed in reverse or out of phase based on t1, t2, and t3; If t1, t2, t3 are not an arithmetic sequence with a common difference of d, and t1, t2, t3 cannot form an arithmetic sequence with a common difference of d, then it is determined that there is a reverse installation situation. If t1, t2, t3 are not an arithmetic sequence with a tolerance of d, but t1, t2, t3 can form an arithmetic sequence with a tolerance of d, then it is determined that there is a mis-phase installation situation. If t1, t2, t3 is an arithmetic sequence with a tolerance of d, then obtain the fault waveforms of the three-phase voltages of A, B, C at the time of the fault in all fault recording files, compare the fault waveforms of the same phase between different fault recording files, and if there are inconsistencies between the same phases, classify the consistent fault waveforms, determine the type of fault waveform that is not the most numerous as the abnormal waveform, and determine that the fault indicator corresponding to the abnormal waveform has a mis-phase installation. Where d is one-third of the period.

2. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: The extreme value moments are either all peak moments or all valley moments.

3. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: The fault waveform is the voltage waveform of the three phases ABC 1-3 cycles after the fault time.

4. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: In the i-th extreme time point, i∈{1,2,3}.

5. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: The method for determining whether an acquisition unit is offline based on the integrity of fault recording data includes: if the measured values ​​of current and voltage in a certain phase are both zero for 12 cycles, it indicates that the corresponding acquisition unit is offline.

6. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: The system also uses the disconnection remote signaling item of the fault indicator to determine whether there is a communication anomaly.

7. The defect identification method for a transient waveform fault indicator according to claim 1, characterized in that: The system also uses the disconnection remote signaling item of the fault indicator acquisition unit to determine whether there is a communication abnormality.

Images